PLD-40 Fiber coupled laser diode, for CNC cutting/engraving

[TomP]

If you have to do a bunch of connections at some point, I have had good luck so far with loctite 648. It has the disadvantage of not leaving an epoxy bead on the end of the connector, but other than that it works well. Cheaper than the epoxy and you might already have it. Main difficulty I have had is it doesn't provide strain relief at the back of the connector, so after my first connection broke I started glueing the connector boot to the jacket to give some strength if the fiber gets pulled on something.

 

[Alaskan]

Well a quick update, I received my epoxy, it's a clear 2 part deal where you break the inner seal and mix it then apply it.

I stripped my fiber to length and slathered it in the epoxy then stuck it into the termination until it bottomed out with a little stripped glass sticking out the end, it says it will cure in 24 hours at room temp so this weekend I will see about scoring the bit sticking out of the tip and try to polish it.

I should have bought some extra connectors and epoxy packets but if I screw this up I will order more and try again, once we get some practice this should be no big deal, my lensed module is finally in the US according to tracking so hopefully I will get it soon, I don't mind buying a lensed connector like the one Buontinh referenced for 150.00 but I really want a big SOB pump of 100W + and I may as well save those funds for the bigger build unless what I buy will work with a 100-500w unit, I like the collimating unit you bought, it should work with a variety of fiber diameters, good choice. :gj:

Good work, looks great. I will keep trailing behind you, when you cut the weeds down ahead of me, makes an easier path to follow Yes, that unit I bought allows me to dink around with lots of fiber choices, that's all I wanted it for and was burning some cardboard the other night using it. I hope you do get a 100 watt unit, blaze that trail for me too

I like the lock tight idea TomP, the results you have are good for me, and glueing the boot on the back too.

 

[paul1598419]

Cool. I have been watching this thread as I am interested in maybe trying this out some day and I'd rather learn from your mistakes than my own. :crackup:

 

[RedCowboy]

That epoxy cured hard, that is the puddle I left out as a test was hard in a day but still tacky on the surface so I gave it another day and my scoring tool took the extra glass off the termination clean, I didn't even get a chance to pull it away, I just stroked across it and it dropped right off, then I used the coarse until the black from the epoxy was gone and then fine sheet to polish in a figure 8 pattern using the puck with a piece of mirror glass under the sheet. I spent only 30 seconds polishing in all and will likely give it a final smoothing until there is no shadow on the camera image of the spot inches away.

The spot is much better, it's round several inches away and looks like it may fit the lensed housing lens dia. without cutting the housing down, maybe.

I do see a slight shadow so I may polish it a little more, but it is a lot better than it was, before I couldn't get a spot visible to my camera 3 inches away, now it's basically round, I need to find the best FL and dia. lens or a primary and BE for this, the fiber end acts as a lens so it adds to the optical train.

Here's a quick test with a G2 in an expedient setup, I think I need to use a longer FL lens, it does punch through the cardboard tube even with the 2.5mm spot.

---EDIT---

I'm going to test some other lenses, I have some of the 16mm wide 30mm FL and 39mm FL that are AR coated for 980 and I am still waiting for a couple more.

Chris do you have any video of burning with your fiber collimator using these 974nm IPG modules or your FAP units ?

Can you get a good tight spot at 10 feet or whatever distance you have and have you calculated any divergence with your fiber collimator, also what FL lens is in your fiber collimator ?

 

[Alaskan]

Thanks, nice. I had a couple of videos showing the FAP burning, but they were on FUbucket. Appreciate you having recorded and sharing/posted that. All I have right now is a raw fiber output I was using with some cardboard, I have all of the polishing stuff and the same connector as you, will soon get mine done too.

 

[RedCowboy]

I bought these strippers and they work great, you can adjust the stop and use the small hole for our glass, I can do it with regular strippers but having the stop set is nice.

You know how to do it, but for our readers I will give a tip: You set the stop so you just bite through the cladding then back off on your grip slightly and strip straight away about 1/4 inch at a time. You don't want to actually bite the glass, just cut into the cladding so it will separate, you have to go by feel, so if you're scrapping but not stripping then adjust the stop screw a fraction of a turn at a time.

https://www.ebay.com/itm/Tri-Hole-H...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649

 

[ChemicalKevy]

Hey guys, I have this laser diode as well.

I was able to cleave and strip the fiber with nothing more than a titanium nitride coated xacto knife and some steady hands... But I went through quite a few inches of fiber before I got the technique down.

I used this connector kit to terminate the fiber (FC): https://www.amazon.com/gp/product/B00TDXYTIY/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1
These lapping sheets to polish the fiber: https://www.amazon.com/gp/product/B074DK653S/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1
Polishing the ceramic ferrule was kind of hard to do by hand. I ordered a polishing puck if I ever burn out the fiber. So far it seems to work fine, the most current I can currently feed the diode is 5 amps, which corresponds to ~12watt output. Pretty impressive for a 100um fiber!


I used this lens to collimate the beam. Its not perfect, but it works. https://www.amazon.com/gp/product/B00MA4HQ60/

Now onto the fun part.. BURNING STUFF!
I modified a cheapo spotting scope (60mm objective) to accept the fiber and collimating lens, and im able to burn my fence 70 feet away. The beam diameter at this distance is only 1/4 inch. The only problem is the collimating lens housing gets kinda warm, so im sure the lens is absorbing some power. Im unsure of the actual power delivered to the fence at 70 feet, but its enough to char the wood within 5 seconds, and can pop balloons instantly!

Ok.. Ill post some photos. my garage is messy don't judge me

Here is the basic setup.

Handy IR indicator card

Too Close! (GIF)


The target is 70 feet away.

I use a GoPro to send video to my phone over WiFi to help me focus the beam.

GIF of burning


So yeah.. very fun laser. If I can find a good telescope for cheap on craigslist i could get much more burning range out of this bad boy! also might buy one of those 140W ones I see on alibaba >

 

[RedCowboy]

Very nice. :gj:

--edited---

Mine takes 12a @ 4.8v but I stop around 10.5 - 11a as it's used, you should have more left in the tank if the same module.

It's nice to see you getting a round spot at 70 over the length of your spotter, I wonder if any of your power could be clipping inside....if you could take a power measure and take it zoomed all the way in and out if your scope is variable power, I have some and an older 20-60X may get used, so if power is lost with the zoom then there may be clipping inside the scope, with the G2 I used the output was still pretty divergent even with the lens very close to the fiber, so primary then big BE such as you are using. It would be interesting to know how much you are putting in vs. getting out? I like it and will do something similar. :beer: